The purpose of the proposed research is to biochemically characterize the collagens from larval and adult Drosophila melanogaster. Preliminary studies have shown that (1) treatment of larvae with -amino-propionitrile allows extraction of collagen in quantities sufficient for further characterization, (2) there are biochemical differences between the larval and adult collagens, suggesting a developmental shift in collagen gene expression, and (3) the Drosophila collagens are more similar to the vertebrate collagen types IV and VII than to the interstitial collagens. The specific goals are to (1) purify native Drosophila collagens, (2) determine the number of collagen types in Drosophila, (3) determine the subunit composition of each type, (4) characterize the denatured subunits, (5) compare larval and adult Drosophila collagen, and (6) compare Drosophila collagens to human collagen, particularly Types IV and VII, looking for structural and functional analogies. Type IV collagen molecules form a mesh-like network that is visable ultrastructurally as the lamina densa of basement membranes. Type VII collagen molecules can be reconstituted into a fiber form that closely resembles anchoring fibrils, which are morphologically identifiable structures that are associated with basement membranes (Murray it al., submitted). Comparison of Drosophila to human collagens will identify conserved structural features that are essential to proper function of collagen in basement membranes and connective tissues. Native collagen molecules will be separated and characterized by a combination of salt fractionation, ion exchange and reverse phase HPLC, electrophoresis and electron microscopy. Isolated molecules and molecular aggregates will be examined by rotary shadowing and negative staining. Denatured subunits will be separated and characterized by ion exchange and reverse phase HPLC, peptide mapping and amino acid analysis. Elucidation of the molecular diversity of the Drosophila collagen family would provide a foundation for future studies in a genetically and developmentally well characterized organism.